The river was too low for us to be out there in a big johnboat, but we had traps to run. We’re experienced river men, and we were doing all right, easing along, watching for deeper channels and underwater obstructions.

Be careful when working near water.

But we failed to see that one rock. We were scanning the bank to find a set we’d made the previous day, angling downstream across the current at about 1/3 throttle. We were concentrating on the bank and not the river when there was a terrific jolt, and the boat slewed sideways.

“Man, you taught that rock a lesson,” I joked, without turning my head. When Bill didn’t answer, I glanced back and learned I was in the boat by myself. Twenty yards upstream, all I could see of Bill were his boots sticking up in the air.

I scrambled back to the motor, and by the time I got the boat turned back upstream, Bill had gotten to his feet and was struggling to stay upright in 2 feet of swift water. I eased the boat alongside, and he fell into it, gasping like a carp and streaming water like a muskrat.

Luckily, the day was mild, but the water temperature was 55 degrees. We went to the bank and got the river poured out of Bill’s boots, and I gave him my dry coat. By that time, he had a dandy goose-egg above his right eye where he’d dead-centered a rock on the bottom of the river. He wasn’t much hurt otherwise, though, except for his dignity, and we finished the run without further incident. We quit early without making any new sets that day. Toward the end, Bill was getting pretty chilly.

The next day, he had a gorgeous shiner, and we were laughing about it and telling everybody we’d gotten into a fight out on the river. But it was the nervous laughter of children walking past a graveyard, because we were thinking: “What if?”

What if the rock Bill hit with the boat had gored a hole in the vessel and it sank? What if the rock he’d hit with his head had knocked him out or fractured his skull? What if the boat had hit another rock and pitched me out while I was trying to get to the motor? What if the water had been 10 feet deep instead of 2? What if it had been 10 degrees that day instead of 45? What if Bill had been alone?

I don’t want to go all soap opera-ish on you here, but there were a bunch of ways that little mishap could have turned into a big one, with consequences we couldn’t have laughed off the next day. Or ever. We were fortunate.

This season, as every season, some trappers across the United States and Canada aren’t going to be so lucky. Many trappers, probably most, are going to have accidents. Most will be minor — fingers or thumbs whacked by traps, sprained ankles, quick dunkings in the creek. But some, like Bill’s recent adventure, will be potentially life-threatening.

There’s no way to avoid them all, except maybe to quit trapping and stay home, but that’s not going to happen. So the next best thing is for us to always make contingency plans. Trap with a partner if possible. Make sure somebody knows where you’re going to be and about when you’re supposed to return. Have a well-stocked first-aid kit in your vehicle. Carry a cell phone, and keep it on you. Protect it in a plastic bag, but have it on you. It’s useless if you can’t reach it.

But mainly — and I know this is repeating something I said in this space this past March, but it can’t be said too often — be careful out there.